deepmodeling · Growl1234 · May 30, 2026 · May 30, 2026 · May 30, 2026 · May 30, 2026
diff --git a/docs/advanced/input_files/input-main.md b/docs/advanced/input_files/input-main.md
@@ -36,6 +36,7 @@
     - [cell\_factor](#cell_factor)
     - [dm\_to\_rho](#dm_to_rho)
     - [chg\_extrap](#chg_extrap)
+    - [wfc\_extrap](#wfc_extrap)
     - [nb2d](#nb2d)
     - [cal\_symm\_repr](#cal_symm_repr)
   - [Input files](#input-files)
@@ -850,6 +851,21 @@
 - **Description**: Charge extrapolation method for MD and relaxation calculations.
 - **Default**: default
 
+### wfc_extrap
+
+- **Type**: String
+- **Description**: Wavefunction extrapolation method for LCAO calculations.
+
+  - none: Disable wavefunction-based extrapolation and use chg_extrap instead.
+  - use_prev_wf: Restore the previous converged ionic-step wavefunctions,
+  reorthonormalize their occupied subspace in the current AO metric, and rebuild rho.
+
+  The first ionic step uses the normal init_wfc/init_chg initialization because no
+  history exists yet. From the second ionic step onward, the selected WFN method
+  must succeed; ABACUS does not silently fall back to charge-density extrapolation.
+  This option is currently limited to Gamma-only LCAO calculations.
+- **Default**: none
+
 ### nb2d
 
 - **Type**: Integer

diff --git a/docs/parameters.yaml b/docs/parameters.yaml
@@ -333,6 +333,23 @@ parameters:
     default_value: default
     unit: ""
     availability: ""
+  - name: wfc_extrap
+    category: System variables
+    type: String
+    description: |
+      Wavefunction extrapolation method for LCAO calculations.
+
+      * none: Disable wavefunction-based extrapolation and use chg_extrap instead.
+      * use_prev_wf: Restore the previous converged ionic-step wavefunctions,
+        reorthonormalize their occupied subspace in the current AO metric, and rebuild rho.
+
+      The first ionic step uses the normal init_wfc/init_chg initialization because no
+      history exists yet. From the second ionic step onward, the selected WFN method
+      must succeed; ABACUS does not silently fall back to charge-density extrapolation.
+      This option is currently limited to Gamma-only LCAO calculations.
+    default_value: none
+    unit: ""
+    availability: ""
   - name: ecutwfc
     category: Plane wave related variables
     type: Real

diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
@@ -691,6 +691,8 @@ if(ENABLE_LCAO)
     ${ABACUS_BIN_NAME}
     PRIVATE
       hamilt_lcao
+      operator_ks_lcao
+      lcao_extrap
       tddft
       orb
       gint

diff --git a/source/source_esolver/esolver_fp.cpp b/source/source_esolver/esolver_fp.cpp
@@ -73,7 +73,9 @@ void ESolver_FP::before_all_runners(BaseCell& basecell, const Input_para& inp)
     this->sf.set(this->pw_rhod, inp.nbspline);
 
     //! 4) init charge extrapolation
-    this->CE.Init_CE(inp.nspin, ucell.nat, this->pw_rhod->nrxx, inp.chg_extrap);
+    this->use_wfc_extrapolation_ = inp.wfc_extrap != "none";
+    this->CE.Init_CE(inp.nspin, ucell.nat, this->pw_rhod->nrxx,
+                     this->use_wfc_extrapolation_ ? "none" : inp.chg_extrap);
 
     //! 5) symmetry analysis should be performed every time the cell is changed
     if (ModuleSymmetry::Symmetry::symm_flag == 1)
@@ -180,9 +182,16 @@ void ESolver_FP::before_scf(UnitCell& ucell, const int istep)
     // charge extrapolation
     if (ucell.ionic_position_updated)
     {
-        this->CE.update_all_dis(ucell);
-        this->CE.extrapolate_charge(&this->Pgrid, ucell, &this->chr, &this->sf,
-                                    GlobalV::ofs_running, GlobalV::ofs_warning);
+        if (this->use_wfc_extrapolation_)
+        {
+            this->sf.setup(&ucell, this->Pgrid, this->pw_rhod);
+        }
+        else
+        {
+            this->CE.update_all_dis(ucell);
+            this->CE.extrapolate_charge(&this->Pgrid, ucell, &this->chr, &this->sf,
+                                        GlobalV::ofs_running, GlobalV::ofs_warning);
+        }
     }
 
     //! Evaluate the vdW correction once for this ionic configuration.

diff --git a/source/source_esolver/esolver_fp.h b/source/source_esolver/esolver_fp.h
@@ -82,6 +82,7 @@ class ESolver_FP : public ESolver
 
     //! charge extrapolation method
     Charge_Extra CE;
+    bool use_wfc_extrapolation_ = false;
 
     //! solvent model
     surchem solvent;

diff --git a/source/source_esolver/esolver_ks_lcao.cpp b/source/source_esolver/esolver_ks_lcao.cpp
@@ -1,4 +1,5 @@
 #include "esolver_ks_lcao.h"
+#include "source_base/global_function.h"
 #include "source_base/module_external/blacs_connector.h"
 #include "source_cell/module_neighbor/sltk_atom_arrange.h"
 #include "source_estate/elecstate_tools.h"
@@ -27,6 +28,7 @@
 #include "source_lcao/LCAO_set.h" // mohan add 20251111
 #include "source_psi/setup_psi.h" // use Setup_Psi for deallocate_psi
 
+
 namespace ModuleESolver
 {
 
@@ -199,12 +201,17 @@ void ESolver_KS_LCAO<TK, TR>::before_scf(UnitCell& ucell, const int istep)
                 this->chr, PARAM.inp.ks_solver);
         }
     }
-    else if(PARAM.inp.esolver_type!="tddft")//if not, use the DMR calculated from last step
+    else if(PARAM.inp.esolver_type!="tddft")//initialize DMR from WFN history if required
     {
-        // 13.1.2) two cases are considered:
-        // 1. DMK in DensityMatrix is not empty (istep > 0), then DMR is initialized by DMK
-        // 2. DMK in DensityMatrix is empty (istep == 0), then DMR is initialized by zeros
-        this->dmat.dm->cal_DMR();
+        if (this->use_wfc_extrapolation_)
+        {
+            this->wf_history_lcao_.initialize_gamma_density(
+                *hamilt_lcao, this->pv, *(this->psi), this->pelec->wg, *(this->dmat.dm), this->chr);
+        }
+        else
+        {
+            this->dmat.dm->cal_DMR();
+        }
     }
     // 13.2) init_scf, should be before_scf? mohan add 2025-03-10
     elecstate::init_scf(ucell, this->Pgrid, this->sf.strucFac, this->locpp.numeric,
@@ -570,6 +577,11 @@ void ESolver_KS_LCAO<TK, TR>::after_scf(UnitCell& ucell, const int istep, const
             this->rdmft_solver, this->deepks, this->exx_nao,
             this->conv_esolver, this->scf_nmax_flag, istep);
 
+    if (conv_esolver && this->psi != nullptr && this->use_wfc_extrapolation_)
+    {
+        this->wf_history_lcao_.update_after_scf(istep, *(this->psi), this->pelec->wg);
+    }
+
     //! 3) Clean up RA, which is used to serach for adjacent atoms
     if (!PARAM.inp.cal_force && !PARAM.inp.cal_stress)
     {

diff --git a/source/source_esolver/esolver_ks_lcao.h b/source/source_esolver/esolver_ks_lcao.h
@@ -10,6 +10,7 @@
 #include "source_lcao/setup_exx.h" // for exx, mohan add 20251008
 #include "source_lcao/module_rdmft/rdmft.h" // rdmft
 #include "source_lcao/setup_dm.h" // mohan add 2025-10-30
+#include "source_lcao/module_extrap/wf_history_lcao.h"
 
 #include <memory>
 
@@ -81,6 +82,8 @@ class ESolver_KS_LCAO : public ESolver_KS
     //! Add density matrix class, mohan add 2025-10-30
     LCAO_domain::Setup_DM<TK> dmat;
 
+    ModuleExtrap::WfHistoryLCAO<TK> wf_history_lcao_;
+
 
     // For deepks method, mohan add 2025-10-08
     Setup_DeePKS<TK> deepks;

diff --git a/source/source_io/module_parameter/input_parameter.h b/source/source_io/module_parameter/input_parameter.h
@@ -50,6 +50,7 @@ struct Input_para
     std::string init_chg = "atomic";    ///< "file","atomic"
     bool dm_to_rho = false;             ///< read density matrix from npz format and calculate charge density
     std::string chg_extrap = "default"; ///< xiaohui modify 2015-02-01
+    std::string wfc_extrap = "none";   ///< wavefunction extrapolation method for LCAO calculations
     bool init_vel = false;              ///< read velocity from STRU or not  liuyu 2021-07-14
 
     std::string input_file = "INPUT";   ///< input file name

diff --git a/source/source_io/module_parameter/read_input_item_system.cpp b/source/source_io/module_parameter/read_input_item_system.cpp
@@ -920,6 +920,50 @@ Available options are:
         };
         this->add_item(item);
     }
+    {
+        Input_Item item("wfc_extrap");
+        item.annotation = "none; use_prev_wf";
+        item.category = "System variables";
+        item.type = "String";
+        item.description = R"(Wavefunction extrapolation method for LCAO calculations.
+
+* none: Disable wavefunction-based extrapolation and use chg_extrap instead.
+* use_prev_wf: Restore the previous converged ionic-step wavefunctions,
+  reorthonormalize their occupied subspace in the current AO metric, and rebuild rho.
+
+The first ionic step uses the normal init_wfc/init_chg initialization because no
+history exists yet. From the second ionic step onward, the selected WFN method
+must succeed; ABACUS does not silently fall back to charge-density extrapolation.
+This option is currently limited to Gamma-only LCAO calculations.)";
+        item.default_value = "none";
+        read_sync_string(input.wfc_extrap);
+        item.check_value = [](const Input_Item& item, const Parameter& para) {
+            if (para.input.wfc_extrap != "none" && para.input.wfc_extrap != "use_prev_wf")
+            {
+                ModuleBase::WARNING_QUIT("ReadInput", "wfc_extrap should be none or use_prev_wf");
+            }
+            if (para.input.wfc_extrap == "use_prev_wf")
+            {
+                if (para.input.basis_type != "lcao")
+                {
+                    ModuleBase::WARNING_QUIT("ReadInput", "WFN-based extrapolation is available only for LCAO");
+                }
+                if (!para.input.gamma_only)
+                {
+                    ModuleBase::WARNING_QUIT("ReadInput", "WFN-based extrapolation is not implemented for k-points");
+                }
+                if (para.input.esolver_type == "tddft")
+                {
+                    ModuleBase::WARNING_QUIT("ReadInput", "WFN-based extrapolation is not implemented for tddft");
+                }
+                if (para.input.nspin == 4)
+                {
+                    ModuleBase::WARNING_QUIT("ReadInput", "WFN-based extrapolation is not implemented for nspin = 4");
+                }
+            }
+        };
+        this->add_item(item);
+    }
     {
         Input_Item item("ecutwfc");
         item.annotation = "energy cutoff for wave functions";

diff --git a/source/source_io/test/read_input_ptest.cpp b/source/source_io/test/read_input_ptest.cpp
@@ -182,6 +182,7 @@ TEST_F(InputParaTest, ParaRead)
     EXPECT_EQ(param.inp.mem_saver, 0);
     EXPECT_EQ(param.inp.init_chg, "atomic");
     EXPECT_EQ(param.inp.chg_extrap, "atomic");
+    EXPECT_EQ(param.inp.wfc_extrap, "use_prev_wf");
     EXPECT_EQ(param.inp.out_freq_elec, 50);
     EXPECT_EQ(param.inp.out_freq_ion, 0);
     EXPECT_EQ(param.inp.out_freq_td, 0);

diff --git a/source/source_io/test/support/INPUT b/source/source_io/test/support/INPUT
@@ -57,6 +57,7 @@ scf_thr_type                   2 #type of the criterion of scf_thr, 1: reci drho
 init_wfc                       atomic #start wave functions are from 'atomic', 'atomic+random', 'random' or 'file'
 init_chg                       atomic #start charge is from 'atomic' or file
 chg_extrap                     atomic #atomic; first-order; second-order; dm:coefficients of SIA
+wfc_extrap                     use_prev_wf #Gamma-only LCAO wavefunction initialization
 out_chg                        0 #>0 output charge density for selected electron steps
 out_pot                        2 #output realspace potential
 out_wfc_pw                     0 #output wave functions

diff --git a/source/source_lcao/CMakeLists.txt b/source/source_lcao/CMakeLists.txt
@@ -5,32 +5,9 @@ add_subdirectory(module_deltaspin)
 
 if(ENABLE_LCAO)
     add_subdirectory(module_operator_lcao)
-    list(APPEND objects
+    add_subdirectory(module_extrap)
+    set(hamilt_lcao_sources
         hamilt_lcao.cpp
-        module_operator_lcao/operator_lcao.cpp
-        module_operator_lcao/veff_lcao.cpp
-        module_operator_lcao/veff_dh.cpp
-        module_operator_lcao/meta_lcao.cpp
-        module_operator_lcao/op_dftu_lcao.cpp
-        module_operator_lcao/deepks_lcao.cpp
-        module_operator_lcao/op_exx_lcao.cpp
-        module_operator_lcao/overlap.cpp
-        module_operator_lcao/overlap_fs.cpp
-        module_operator_lcao/ekinetic.cpp
-        module_operator_lcao/ekinetic_fs.cpp
-        module_operator_lcao/ekinetic_dh.cpp
-        module_operator_lcao/nonlocal.cpp
-        module_operator_lcao/nonlocal_dh.cpp
-        module_operator_lcao/nonlocal_fs.cpp
-        module_operator_lcao/td_ekinetic_lcao.cpp
-        module_operator_lcao/td_nonlocal_lcao.cpp
-        module_operator_lcao/td_pot_hybrid.cpp
-        module_operator_lcao/td_pot_hybrid_fs.cpp
-        module_operator_lcao/dspin_lcao.cpp
-        module_operator_lcao/dspin_fs.cpp
-        module_operator_lcao/dftu_lcao.cpp
-        module_operator_lcao/dftu_fs.cpp
-        module_operator_lcao/operator_fs_utils.cpp
         dftu_lcao.cpp
         pulay_fs_center2.cpp
         FORCE_STRESS.cpp
@@ -44,9 +21,9 @@ if(ENABLE_LCAO)
         spar_st.cpp
         spar_u.cpp
         LCAO_set.cpp
-		LCAO_set_fs.cpp
-		LCAO_set_st.cpp
-		LCAO_nl_mu.cpp	
+        LCAO_set_fs.cpp
+        LCAO_set_st.cpp
+        LCAO_nl_mu.cpp
         LCAO_set_zero.cpp
         LCAO_allocate.cpp
         LCAO_set_mat2d.cpp
@@ -56,7 +33,7 @@ if(ENABLE_LCAO)
         setup_deepks.cpp
         setup_dm.cpp
         rho_tau_lcao.cpp
-		record_adj.cpp
+        record_adj.cpp
         center2_orb.cpp
         center2_orb-orb11.cpp
         center2_orb-orb21.cpp
@@ -67,7 +44,7 @@ if(ENABLE_LCAO)
     add_library(
         hamilt_lcao
         OBJECT
-        ${objects}
+        ${hamilt_lcao_sources}
     )
 
     if(ENABLE_COVERAGE)

diff --git a/source/source_lcao/module_extrap/CMakeLists.txt b/source/source_lcao/module_extrap/CMakeLists.txt
@@ -0,0 +1,15 @@
+add_library(
+    lcao_extrap
+    OBJECT
+    wf_history_lcao.cpp
+    wf_orthonormalize_lcao.cpp
+    wf_density_init_lcao.cpp
+)
+
+if(BUILD_TESTING)
+  add_subdirectory(test)
+endif()
+
+if(ENABLE_COVERAGE)
+  add_coverage(lcao_extrap)
+endif()
diff --git a/source/source_lcao/module_extrap/test/CMakeLists.txt b/source/source_lcao/module_extrap/test/CMakeLists.txt
@@ -0,0 +1,9 @@
+AddTest(
+  TARGET MODULE_LCAO_extrap_test
+  LIBS parameter ${math_libs} psi base device
+  SOURCES
+    wf_extrap_test.cpp
+    ../wf_history_lcao.cpp
+    ../wf_orthonormalize_lcao.cpp
+    ${ABACUS_SOURCE_DIR}/source_basis/module_ao/parallel_orbitals.cpp
+)